The invention relates to processes for producing bags and packaging processes for substances.
In U.S. Pat. No. 4,909,017, a device is disclosed for producing bags and packaging, in which a tube is formed continuously around a shaping unit from an initially flat plastic film. A chute for supplying a substance to be packaged opens into the inner portion of the forming unit, which opens into the tube. After the forming unit, a first transverse sealing of the tube onto itself is performed so as to form a seal that provides a closed bottom edge for the bag. Then the substance is released and falls into the bag. Next another seal is made above the content of the bag in order to seal the bag and the tube is cut above this second seal in order to provide a sealed closed mouth for the bag and to separate the bag that has been filled in this manner from the rest of the tube. In practice, the upper sealing of one bag and lower sealing of another bag above the first bag are performed simultaneously, and the cut is made between the two seals. In addition, a reclosable fastener strip is sealed transversely onto the film before the film is folded onto itself to form the tube. This strip is then sealed to the opposite side of the bag and extends into the bag at the closed mouth. The strip can be opened by the user in order to obtain access to the substance.
It turns out to be difficult to make this process compatible with certain special types of reclosable fastener strips, for example so-called tamper-proof fasteners or those which involve gluing.
An object of the present invention is to provide a process of a different kind for the production of bags and packaging.